The laser rangefinder, as a contact-less measuring instrument, has already been widely used in the fields of remote control, precise measurement, engineering construction, security monitor and intelligent control, etc. The working principle of the laser rangefinder is: a laser transmitter mainly transmits laser through a laser tube; the laser is reflected by the measured object and detected by a photosensitive diode and then a distance is determined by calculating the difference between the time when the laser is transmitted and the time when the laser is detected.
Currently, all the laser rangefinders can only measure a straight line distance and a target reflector at the destination of the measured object for reflecting the laser must exist. Distance cannot be measured for there is no target reflector or for curve line, polygonal line, thus greatly limiting the application scope of the laser rangefinder.